1. Field of the Invention
The present invention relates generally to semiconductor devices, and more particularly but not exclusively to power transistors.
2. Description of the Background Art
Power transistors are employed in a variety of applications requiring high power dissipation, including power supplies, DC-DC converters, and motor control, to name a few examples. Power transistors are selected for a given application based on their ON-state, switching, and OFF-state characteristics. The design of a power transistor often involves trade-offs among the aforementioned characteristics. For example, in a typical power metal oxide semiconductor field-effect transistor (MOSFET), the drift region is lightly doped to achieve a high breakdown voltage. However, a lightly doped drift region results in a high ON-state resistance.
The following disclosure pertains to a power transistor that achieves relatively low ON-state loss and switch loss for a given breakdown voltage. Advantageously, the power transistor allows for relatively easy fabrication.